Charmonium (bound charm-anticharm states such as the J/psi) is modeled as it evolves through the rapidly changing QCD environment of a high-energy collision. A temperature-independent Hamiltonian handles the nonadiabatic preequilibrium stage and becomes its finite-temperature counterpart at thermal equilibrium, while collisional damping and gluonic dissociation reduce the yield and gluonic-de-excitation regeneration enhances it. The combined transverse-momentum and multiplicity dependence becomes a diagnostic for whether a thermalized QCD medium forms even in small proton-proton collisions.
In ultrarelativistic nuclear collisions the suppression of charmonium (bound charm-anticharm states such as the J/psi) is a classic signature of quark-gluon plasma (QGP). This paper models charmonium…